Gripping shaft

ABSTRACT

Gripping shaft includes one or more longitudinal grooves or slots in which are contained cables or rods that are forced outwardly during rotation of the shaft into wedging engagement between the shaft and a hollow core or coil of stock material inserted thereover for positively gripping the same. An adjustable stop may be provided on the shaft for accommodating different lengths of coils, and means are also provided for adjusting the slack in the cables to suit operating conditions. When rods are used as the gripping elements, additional means may be provided for urging the rods out of gripping engagement with the core or coil when the shaft is stopped so that the rods will not interfere with loading and unloading of the stock material.

United States Patent Fedor GRIPPING SHAFT [72] Inventor: Richard M. Fedor, 2662 Shaker Road, Cleveland Heights, Ohio 44118 [22] Filed: Feb. 24, 1970 [21] Appl.No.: 13,682

[52] US. Cl. ..242/68, 242/46.3, 242/72 [51] Int. Cl. ....B65h 75/30, B65h 75/24, B65h 17/02 [58] Field of Search ..242/68, 68.1, 72, 46.3, 46.4

[56] References Cited UNITED STATES PATENTS 2,582,010 l/ 1952 Crosby ..242/72 3,092,342 6/ 1963 Jackson ..242/72.l X

' Primary Examiner-George F. Mautz Assistant Examiner-Gregory A. Walters Attorney-Oberlin, Maky, Donnelly & Renner 51 Aug. 22, 1972 [57] ABSTRACT Gripping shaft includes one or more longitudinal grooves or slots in which are contained cables or rods that are forced outwardly during rotation of the shaft into wedging engagement between the shaft and a hollow core or coil of stock material inserted thereover .for positively gripping the same. An adjustable stop may be provided on the shaft for accommodating different lengths of coils, and means are also provided for adjusting the slack in the cables to suit operating conditions. When rods are used as the gripping elements, additional means may be provided for urging the rods out of gripping engagement with the core or coil when the shaft is stopped so that the rods will not interfere with loading and unloading of the stock material.

22Claim s, 17 Drawing Figures PATENIEDAUB 22 I972 v 3 6 8 5, 7 5 7 sum 1 0r 3 RICHARD M. FEDOI? ATTORNEYS INVENTOR PATENTEDA B I972 3685,75 7

' sum 2 or 3 INVENTOR RICHARD M. FEDOR 5 4 My fiamzdfq 6 dram L A TTORNEYS PATENTED M1522 I972 SHEET 3 0F 3 INVENTOR R/CHARD M. FEDOR ATTORNE'YS GRIPPING SHAFT BACKGROUND OF THE INVENTION This invention relates generally as indicated to a gripping shaft and, more particularly, to a gripping shaft which readily permits insertion of a coil of stock material or core therefor onto the gripping shaft and removal therefrom while the shaft is stationary, and yet positively grips the coil when rotated in one direction or the other to retain the coil in position on the shaft during winding or unwinding of the stock material.

Flexible stock materials such as light gauge metals, paper, and plastics are oftentimes wound into large coils for storage and later use. To facilitate winding of the stock material into such coils and subsequent unwinding of the stock material from the coils, various types of gripping devices have been devised which automatically grip the coils or cores on which the stock material is wound for driving the coils during winding or braking the coils during unwinding. As an example of such a device, reference may be had to U. S. Pat. No. 2,582,010, granted Jan. 8, 1952, which discloses an arbor having slots or grooves therein containing flexible cords or cables which effectively grip a surrounding core when forced outwardly into the shallow side of the grooves. A stop is also provided for the coil.

However, no provision is made for adjusting the stop to accommodate different widths of coils on the shaft, and the slack in the cables is not readily adjustable as may be necessary to facilitate loading and unloading of the coils from the shaft while insuring a positive grip therebetween during rotation. Nor is any provision made for insuring that the cables remain in the deep side of the slots out of gripping engagement with the coils when it is desired to remove the coils from the shaft.

SUMMARY OF THE INVENTION With the foregoing in mind, it is a principal object of this invention to provide a gripping shaft onto which a core or coil of stock material may be readily placed and removed therefrom, and yet the gripping shaft positively grips the core or coil during winding and unwinding of the stock material.

Another object is to provide in certain embodiments of the invention a gripping shaft with an adjustable stop for accommodating different widths of stock material.

Still another object is to provide in certain embodiments of the invention a gripping shaft utilizing flexible cables as the gripping elements that are wedged between the core and shaft during rotation of the shaft for positively gripping the coil of stock material during rotation, and means for varying the amount of slack in the cables.

A further object is to provide in still other embodiments of the invention a gripping shaft utilizing rods as the gripping elements that are wedged between the shaft and core or coil during rotation of the shaft for positively gripping the coil during rotation, and means for returning the rods to a position out of wedging engagement with the core or coil when the shaft is stopped so as not to interfere with loading of the core or coil onto the shaft and removal therefrom.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS In the annexed drawings:

FIG. 1 is a partial side elevation view of a preferred form of gripping shaft constructed in accordance with this invention, having portions broken away to show the manner of securing the ends of a gripping cable in a groove provided therefor in the shaft;

FIG. 2 is an end elevation view of the gripping shaft of FIG. 1 as seen from the plane of the line 22 at the left end of FIG. 1;

FIG. 3 is a transverse section through the gripping shaft of FIG. 1, taken on the plane of the line 3-3;

FIG. 4 is a transverse section similar to FIG. 3, but showing a gripping shaft in which plural grooves are provided for receipt of plural gripping cables;

FIG. 5 is a partial side elevation view of another form of gripping shaft constructed in accordance with this invention, having portions broken away to show the details of a modified form of slack adjustment device for the gripping cable;

FIG. 6 is a transverse section through the gripping shaft of FIG. 5, taken on the plane of the line 66 thereof;

FIG. 7 is a partial side elevation view of yet another form of gripping shaft constructed in accordance with this invention, having portions broken away to show other means for adjusting the slack in the gripping cable;

FIG. 8 is an end elevation view of the gripping shaft of FIG. 7 as seen from the plane of the line 8-8 at the left end thereof;

FIG. 9 is a side elevation view of still another form of gripping shaft in accordance with this invention, having portions broken away to show the details of another form of slack adjustment device for the gripping cable;

FIG. 10 is a transverse section through the gripping shaft of FIG. 9, taken on the plane of the line 1010;

FIG. 11 is a partial side elevation view of still another form of gripping shaft in accordance with this invention;

FIG. 12 is a side elevation view of sill another form of gripping shaft constructed in accordance with this invention in which a gripping rod is used in place of the gripping cables of the previous embodiments, and portions are broken away to show the connections between the end collars at the ends of the gripping shaft and the ends of the gripping rod;

FIG. 13 is an end elevation view of the gripping shaft of FIG. 12 as seen from the plane of the line 13-13 of FIG. 12 at the left end thereof;

FIG. 14 is a transverse section through the gripping shaft of FIG. 12, with portions of the inboard collar and plate attached thereto broken away to show the spring plunger in the collar for returning the gripping rod to a position where it will not interfere with loading of a core or coil onto the shaft and removal therefrom;

FIG. 15 is a side elevation view of yet another form of gripping shaft in accordance with this invention also utilizing gripping rods instead of gripping cables, with portions of the inboard collar broken away to show the connection between the inboard collar and gripping rods;

FIG. 16 is an end elevation view of the gripping shaft of FIG. 15 as seen from the plane of the line 16-16 of FIG. 15 at the left end thereof; and

FIG. 17 is a transverse section through the gripping shaft of FIG. 15, with portions of the inboard collar broken away to show the configuration of the holes in the inboard collar which receive the upturned inboard ends of the gripping rods.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the drawings and first especially to FIGS. 1 through 3 thereof, there is illustrated one embodiment of a gripping shaft 1 in accordance with this invention comprising a shaft 2 mounted for rotation in suitable journals shown schematically at 3 at the inboard end of the shaft 2. Preferably, the shaft 2 is substantially solid in section to increase the load capabilities of the shaft, but it will be apparent that the shaft may be made hollow if desired. Moreover, although the shaft 2 is most commonly disposed in a horizontal position as shown, it will be apparent that such shaft may also be vertically oriented if desired.

Formed in the outer surface of the shaft 2 as by milling is one or more longitudinally extending slots or grooves 5 in which is contained a flexible cable .6 preferably of twisted metal wire. As best seen in FIGS. 2 and 3, the slot 5 has a back wall 7 and bottom wall 8 which intersect at substantially right angles to each other, and the depth of the slot adjacent the back wall 7 is somewhat greater than the diameter of the cable 6, whereby when the cable is disposed in the slot adjacent the back wall 7 it will not interfere with insertion of a hollow core 9 or coil 10 of stock material onto the shaft or removal therefrom. However, the depth of the slot 5 decreases remote from the back wall 7, and if the cable 5 is moved outwardly along the bottom wall 8 of the groove as by rotating the shaft 2 in a counter-clockwise direction relative to the coil 10 as seen in FIG. 2, the cable will become wedged between the coil 10 and shaft 2, thereby positively gripping the coil for rotation with the shaft.

To retain the cable 6 within the slot 5 without the core 9 or coil 10 in position, there is provided a pair of collars 11 and 12 on opposite ends of the shaft. The shaft 2 has a reduced end portion 13 on the outboard end thereof for receipt of the collar 11 which desirably has a maximum diameter no greater than the outer diameter of the shaft 2 so as not to interfere with insertion of a core 9 or coil 10 onto the shaft 2 from the outboard end and removal therefrom. An opening 14 is provided in the collar 11 through which one end 15 of the cable 6 extends, and a sleeve or ferrule 16 is crimped or brazed to the end of the cable 6 outwardly of the collar 11 to prevent pulling of that end of the cable through the collar. One or more set screws 17 may be provided in the collar 11 for releasably locking the collar in position on the shaft.

The other collar 12 which is located adjacent the inboard end of the shaft 2 may also be releasably retained against rotation on the shaft by tightening one or more set screws 18 received in tapped openings 19 in the collar 112, and an additional set screw 20 received in another tapped opening 21 in the collar 12 may be tightened into clamping engagement with the inboard end 22 of the cable 6 for releasably clamping that end of the cable to the shaft. The amount of slack in the cable 6 controls the amount of permissible movement of the cable from the non-wedging position shown in FIG. 3 adjacent the back side 7 of the groove to the wedging position away from such back side, which slack may be preset by loosening and tightening the set screw 20.

An additional collar 25 may also be provided intermediate the collars 11 and 12 which may be of a construction substantially identical to the collar 12 and adjustable longitudinally between such collars to act as an adjustable stop for the core or coil to accommodate different widths. The collar 25 also permits additional adjustment in the slack of the cable 6 through tightening of its set screw 26 into engagement with the cable anywhere along the length thereof.

When the shaft 2 is stationary, the slack in the cable 6 may be taken up by extension of the cable through the opening 14 in the collar 11 to permit full engagement of the cable with the back wall of the groove where it will not interfere with proper placement of the core 9 or coil 10 onto the shaft and removal therefrom. However, when the shaft 2 is rotated in a counterclockwise direction relative to the core as viewed in FIG. 2, the cable 6 is thrown out by centrifugal force into wedging engagement between the core and shaft to provide automatic gripping of the core for winding stock material onto the core during rotation of the shaft. Removal of the wound stock and core from the shaft is obtained by rotating the shaft in the opposite direction approximately one quarter turn while keeping the stock stationary to disengage the cable from the core, after which the core and coil may be readily slid off the shaft.

To unwind the stock from a coil, the coil is inserted onto the shaft 2 and the stock is pulled off in a direction tending to rotate the shaft 2 in a clockwise direction as viewed in FIG. 2 so that the slight drag of the stock or core will pull the cable 6 outwardly into wedging engagement between the core and shaft causing the shaft to rotate with the coil. The speed of rotation of the shaft and thus rate of unwinding of the coil may be controlled by a brake or drag applied to the shaft. When the stock is completely unwound from the coil, the core may be removed from the shaft by gripping the core by hand and rotating the core in the opposite direction relative to the shaft approximately one quarter turn to disengage the cable from wedging engagement between the core and shaft.

To prevent inadvertent pulling of the inboard end of the cable 6 through the inboard collar 12 when the set screw 20 is loosened, a sleeve 27 may be releasably clamped to the innermost end of the cable using a set screw 23 or the like, and a garter spring 24 may be placed around the inboard end of the shaft and over the innermost end of the cable as shown in FIG. 1 to prevent such inner end from flying out during rotation thereof. Moreover, while only one slot 5 and one gripping cable 6 is provided in the gripping shaft 1 of the FIGS. 1 through 3 embodiment, it will be apparent that additional slots 5 equally spaced around the outer periphery of the shaft may be provided for receipt of additional gripping cables 6 as shown in FIG. 4. In that event, the collar 11 would be provided with a corresponding number of holes 14 for receipt of the outboard ends of the cables, and the collar 12 would be provided with additional set screws for releasably clamping the inboard ends of all of the cables against the shaft as further shown in FIG. 4.

Other means than the collars 12 or may also be used to provide the correct slack in the gripping cables to suit certain requirements. Thus, for example, in FIGS. 5 and 6 thereis shown a modified form of inboard collar including a slack adjustment device 31 which may be used in place of the collar 12 of FIGS. 1 through 3, with or without the additional collar 25, depending upon whether there is a need for a longitudinally adjustable stop for the core 9 and coil 10. Set screws 29 may still be used for clamping the collar 30 to the shaft 2. However, in place of the set screws 20 for releasably clamping the inboard end of the gripping cable to the shaft, the inboardcollar 30 is provided.

with a longitudinal slot 32 in which is received a guide member or sleeve 33 having an opening 34 therethrough in which is crimped or brazed the inboard end of the cable 6.

The maximum extent to which the guide member 33 may be moved within the slot 32 toward the outboard end of the shaft is limited by a threaded pin or rod 35 projecting from the inboard end of the guide member 33 through a washer 36 which overlies the inboard end of the collar 30 and prevents movement of a pair of nuts 37 threaded onto the rod 35 beyond the inboard end of the collar. Varying the longitudinal position of the nuts 37 on the rod 35 will vary the amount of slack in the cable which is thrown out by centrifugal force during rotation of the shaft in a counterclockwise direction as viewed in FIG. 6. However, the slack adjustment device 31 of FIGS. 5 and 6 still permits the cable to straighten out in a longitudinal direction during reverse rotation of the shaft while retaining the coil stationary to completely disengage the cable from the coil for easy sliding of the core and coil from the shaft.

If desired, the amount of slack in the cable 6 may be made positive in both directions by using an inboard collar 40 such as shown in FIGS. 7 and 8 in place of the inboard collar 30 of the FIGS. 5 and 6 embodiment. The primary difference between the inboard collar 40 of FIGS. 7 and 8 and inboard collar of FIGS. 5 and 6 is that instead of providing nuts 37 on the free end of the rod 35, a single nut 41 on the rod is confined between a pair of washers 42 within a radially extending crescentshaped slot 43 in the collar, whereby rotation of the nut 41 in opposite directions will cause longitudinal movement of the guide member 33 within the longitudinal slot 32 in opposite directions for adjusting the amount of slack in the cable 6.

Remote adjustment of the slack in the cable 6 may also be achieved for easy core or coil positioning by providing a cylinder 45 on the inboard end of the shaft having a rod 46 extending through a longitudinal bore 47 in the shaft for attachment to the outboard collar 1 I as further shown in FIGS. 7 and 8. By using a rotating union 48 for connecting the cylinder 45 to an air line or hydraulic line, the amount of slack in the cable 6 may be controlled under running conditions by remote control of the cylinder 45 within the range of the cylinder stroke and the maximum permissible amount of slack in the cable which may be mechanically preset by any one of the slack adjustment devices previously described. A guide pin may extend from the end of the shaft 2 through an opening in the collar 11 to prevent relative rotation as shown in FIG. 7.

In FIGS. 9 and 10 there is shown a gripping shaft which may be of a construction like any of the gripping shafts previously described, including a shaft 2 having a longitudinally extending slot or groove 5 in which is disposed a gripping cable 6 whose ends are retained in place by a pair of collars l1 and 12. A removable bearing support 49 may be attached to the outboard end of the shaft to provide additional support therefor if desired.

Inserted over the shaft 2 is a gripping sleeve 50 which is positively held in place by the cable 6 and such gripping sleeve has its own longitudinal groove 51 containing a cable 52 for use in releasably gripping a larger diameter core or coil than the shaft 2. Secured to opposite ends of the gripping sleeve 50 are a pair of collars 54 and 55 having apertures therethrough for receipt of the ends of the gripping cable. The outboard collar 54 is of a diameter no greater than the outer diameter of the gripping sleeve 50 so as not to interfere with insertion of a core onto the gripping sleeve or removal therefrom, whereas the inboard collar 55 may be of a larger diameter to provide a stop for the core.

A sleeve or ferrule 16 may be crimped or brazed to the outboard end of the gripping cable 52 to prevent such end from being pulled through the outboard collar 54, and a slack adjustment device may be provided on the inboard end of the gripping cable 52 which may consist of an externally threaded sleeve 61 brazed to the end of the cable and having threaded engagement with a pair of nuts 62 exteriorly of a boss 63 on the collar 55. For ease of adjustment of the sleeve 61, a screwdriver slot 64 may be provided in the outer end thereof.

In FIG. 11 there is shown still another form of gripping shaft 65 in accordance with this invention which is identical to the gripping shaft of the previous embodiments in the provision of a longitudinal groove 5 in the outer periphery of the shaft for receipt of a gripping cable 6 therein. Moreover, a collar 67 similar to the collar 11 of the FIGS. 1 through 3 embodiment may be used to releasably retain the inboard end of the gripping cable against movement. However, instead of using an outboard collar for retaining the outboard end of the gripping collar 6, a sleeve or ferrule 68 is crimped or brazed to the outboard end of the cable and is directly secured to the outboard end of the shaft as by using a screw 69. Moreover, the outboard end of the shaft is desirably tapered sufficiently to provide clearance between the ferrule i -tand the maximum outer diameter of the gripping shaft so as not to interfere with insertion of a core or coil onto the gripping shaft and removal therefrom.

Referring next to FIGS. 12 through 14, there is shown a modified form of gripping shaft 76 in which a rigid metal rod 71 is disposed in a longitudinal groove 72 therein in place of the flexible cable 6 of the previous embodiments. For retaining the rod 71 within the groove 72, there is provided an inboard collar 73 on the gripping shaft 70 which is fixed to the gripping shaft and surrounds the inboard end of the rod. The outboard end of the gripping shaft has an end portion 74 of substantially reduced diameter to which is secured an outboard collar 75 having a maximum diameter no greater than the maximum diameter of the gripping shaft so as not to interfere with insertion of a core or coil thereover and removal therefrom.

Extending completely through the outboard collar 75 is a radial slot 76 for receipt of the outboard end of the rod 71 which is reversely bent adjacent the outboard end for extension into the radial slot as shown. A garter spring 77 or the like may be disposed around the outboard end of the rod 71 and reduced end portion 74 of the gripping shaft for yieldably maintaining the rod 71 in position adjacent the back side 80 of the groove 72 where it will not interfere with insertion of a core or coil onto the gripping shaft and removal therefrom. However, when the gripping shaft 70 is rotated in a counter-clockwise direction as viewed in FIGS. 13 and 14, the rod 71 is thrown outwardly by centrifugal force into wedging engagement between the core and gripping shaft for locking the core to the shaft.

The radial slot 76 in the collar 75 limits the outward travel of the outboard end of the rod 71 within the groove 72, and a slot 81 within the inboard collar 73 (see FIG. 14) limits outward travel of the inboard end of the rod. Also provided within the inboard collar 73 is a spring plunger 82 which is compressed by the rod 71 during outward movement within the groove 72 and assists the garter spring 77 in returning the rod 71 to the disengaged position when the shaft is rotated in the reverse direction relative to the core. Adjustment of FIGS. 15 through 17 show a modified form of gripping shaft 86 in which plural longitudinal grooves 87 are provided for receipt of plural gripping rods 88. For retaining the gripping rods 88 within the grooves 87, there is provided a pair of collars 89 and 90 adjacent opposite ends of the gripping rods. Preferably, the inboard ends 91 of the gripping rods 88 are turned outwardly for receipt in radial openings 92 in the in board collar 90, and the gripping rods 88 are reversely bent adjacent the outboard ends 93 for extension through longitudinal openings 94 in the outboard collar 89 which is received on a reduced end portion 95 of the gripping shaft and has a maximum diameter no greater than the outer diameter of the gripping shaft.

Both collars 89 and 90 are also free to rotate on the gripping shaft, whereby when the gripping rods 88 are urged outwardly in the slots by centrifugal force, such gripping rods will move simultaneously because of their connections with the collars 89 and 90 for providing a uniform grip between the gripping shaft and core inserted thereover. Such gripping action may also be enhanced as by serrating the gripping portions of the rods 88.

During outward movement of the gripping rods 88 within the shafi grooves 87 provided therefor, the rods have a tendency to rotate due to their connections with the outboard collar 89, and accordingly, the radial openings 92 in the inboard collar are desirably countersunk or tapered as shown in FIGS. 15 and 17 to allow for such movement without twisting the rods. Snap rings 96 may be provided on either side of the outboard collar 89 to retain the collar against axial movement while permitting rotation thereof, and coil springs 97 and 98 having one end secured to the gripping shaft and the other end secured to the respective collars 89 and 90 assist in returning the collars and rods to the non-gripping position upon disengagement of the gripping rods with the core as by turning the shaft a quarter turn in the reverse direction.

From the foregoing, it will now be apparent that the various forms of gripping shafts disclosed herein provide for positive gripping of a core or coil without any obstruction in loading and unloading of the core or coil from the shaft as desired. The gripping cables or rods are ordinarily maintained in the non-wedging position except when a force is applied to the cables or shafts urging them into the locking position. Various devices are also provided for varying the amount of slack in the gripping cables as required for a particular operation. Moreover, while certain of the disclosed gripping shaft embodiments include only a single gripping cable or rod, it will be apparent that plural cables or rods may be provided as desired without departing from the scope of the present invention. Similarly, while the grooves for the gripping cables and rods are shown as being substantially straight, they may be made spiral or helical to better distribute the gripping force around the periphery of the core if desired.

I, therefore, particularly point out and distinctly claim as my invention:

1. A gripping shaft comprising a shaft portion, a groove in the outer periphery of said shaft portion having a back wall and bottom wall, a gripping element received in said groove, said groove having a depth adjacent said back wall which is greater than the diameter of said gripping element for receipt of said gripping element so as not to interfere with placement of a member onto said shaft portion and removal therefrom, said groove being of less depth in a direction away from said back wall for wedging said gripping element between said shaft portion and member placed thereover when said gripping element is moved along said bottom wall away from said back wall, and means for retaining during rotation at least one end of said gripping element in a fixed position against movement in a direction away from said back wall of said groove.

2. The gripping shaft of claim 1 wherein said means for retaining at least one end of said gripping element against movement as aforesaid comprises a collar fixed to said shaft for rotation therewith, and means connecting said one end of said gripping element to said collar.

3. The gripping shaft of claim 1 wherein means are provided for retaining the other end of said gripping element against movement in a direction away from said back wall of said groove, said gripping element comprising a flexible member having sufl'icient slack therein to permit outward movement of said flexible member intermediate the ends thereof into wedging engagement between said shaft portion and a member inserted thereover.

4. The gripping shaft of claim 3 wherein said means for retaining one end of said gripping element against movement comprises a collar fixed to said shaft for rotation therewith.

5. The gripping shaft of claim 4 wherein said collar is axially adjustable to vary the slack in said flexible member.

6. The gripping shaft of claim 4 further comprising an aperture in said collar through which said one end of said flexible member extends, and a sleeve on the projecting end of said flexible member which permits said flexible member to straighten out adjacent said back wall when no force is applied to said flexible member, and limits the outward movement of said flexible member in said groove by engagement of said sleeve with said collar when a force is applied to said flexible member urging said'flexible member outwardly in said groove.

7. The gripping shaft of claim-3 wherein said means for retaining the ends of said flexible member against movement comprises a pair of collars fixed to said shaft in axially spaced relation for rotation therewith, one of said collars being axially adjustable relative to the other for varying the slack in said flexible member.

.8. The gripping shaft of claim 7 wherein said axially adjustable collar is of a diameter greater than the diameter of said shaft portion to provide an adjustable stop for accommodating members of different widths on said shaft portion.

9. The gripping shaft of claim 1 wherein said gripping element is a flexible member having sufficient slack therein to permit outward movement of said flexible member into wedging engagement between said shaft portion and a member inserted thereover, and a slack adjustment device is provided for varying the amount of slackin said flexible member, said slack adjustment device comprising a collar on said shaft portion containing a longitudinal slot, a guide member received in said longitudinal slot, one end of said flexible member being secured to said guide member, and means for limiting movement of said guide member. within said slot in a direction increasing the slack in said flexible member.

10. The gripping shaft of claim 9 wherein said lastmentioned means comprises a threaded rod on said guide member, an adjustable nut on said threaded rod, and a washer on said rod between said collar and nut which prevents movement of said nut into said slot.

11. The gripping shaft of claim 9 wherein. said lastmentioned means comprises a threaded rod on said guide member, an adjustable nut on said threaded rod, and a radial slot in said collar for confining said nut against longitudinal movement, whereby rotation of said nut in opposite directions causes longitudinal adjustment of said guide member in opposite directions.

12. The gripping shaft of claim 4 wherein the other end of said flexible member has a ferrule thereon for direct attachment to the outboard end of said shaft portion.

13. The gripping shaft of claim 12 wherein said outboard end of said shaft portion is sufficiently tapered to provide clearance between said ferrule and the maximum outer diameter of said shaft portion.

14. The gripping shaft of claim 1 wherein said gripping element comprises a rigid rod, and means for retaining one end of said rod against movement comprises a collar fixed to said shaft portion for rotation therewith, said collar having a radial slot therein, and said rod having a reverse bend adjacent the outboard end thereof to permit extension of said outboard end of said rod into said radial slot in said collar.

15. The gripping shaft of claim 14 further comprising means for urging said rod toward said back wall of said groove.

16. The gripping shaft of claim 15 wherein said lastmentioned means comprises a garter spring disposed around the outboard end of said rod and said shaft portion.

17. The gripping shaft of claim 14 further comprising a second collar fixed to said shaft portion axially spaced from said first-mentioned collar surrounding the other end of said rod, said second collar having a slot in alignment with said groove in said shaft portion for limiting outward movement of said rod in said groove, and an adjustable spring plunger in said second collar which is compressed by said rod during such outward movement for urging said rod toward said back wall of said groove.

18. A gripping shaft comprising a shaft portion, a groove in the outer periphery of said shaft portion having a back wall and bottom wall, a gripping element received in said groove, said groove having a depth adjacent said back wall which is greater than the diameter of said gripping element for receipt of said gripping element so as not to interfere with placement of a member onto said shaft portion and removal therefrom, said groove being of less depth in a direction away from said back wall for wedging said gripping element between said shaft portion and member placed thereover when said gripping element is moved along said bottom wall away from said back wall, said gripping element comprising a rigid rod, and means for urging said rod toward said back wall of said groove.

19. The gripping shaft of claim 18 further comprising a pair of axially spaced collars surrounding the ends of said rod,- one of said collars being received on a reduced diameter portion at the outboard end of said shaft portion, said one collar having a maximum diameter no greater than the maximum diameter of said shaft portion, and a radial slot in said one collar, said rod having a reverse bend adjacent the outboard end thereof to permit extension of said outboard end of said rod into said radial slot in said one collar.

20. The gripping shaft of claim 19 wherein said means for urging said rod toward said back wall of said groove comprises a garter spring disposed around the outboard end of said rod and reduced end portion of said shaft portion.

21. The gripping shaft of claim 18 wherein said shaft portion hasa plurality of said grooves for receipt of a plurality of said rods, and there are a pair of axially spaced collars surrounding opposite ends of said rods, one of said collars being received on a reduced diameter portion at the outboard end of said shaft portion, said one collar having a maximum diameter no greater than the maximum diameter of said shaft portion, and a plurality of axial openings in said one collar, said rods being reversely bent adjacent the outboard ends thereof to permit extension of said outboard ends of said rods into said longitudinal openings in said one collar, and the other collar having radial openings therein inserted thereover.

22. The gripping shaft of claim 19 wherein said means for urging said rod toward said back wall of said groove comprises a pair of coil springs having one end secured to said shaft portion and the other end secured to the respective collars. 

1. A gripping shaft comprising a shaft portion, a groove in the outer periphery of said shaft portion having a back wall and bottom wall, a gripping element received in said groove, said groove having a depth adjacent said back wall which is greater than the diameter of said gripping element for receipt of said gripping element so as not to interfere with placement of a member onto said shaft portion and removal therefrom, said groove being of less depth in a direction away from said back wall for wedging said gripping element between said shaft portion and member placed thereover when said gripping element is moved along said bottom wall away from said back wall, and means for retaining during rotation at least one end of said gripping element in a fixed position against movement in a direction away from said back wall of said groove.
 2. The gripping shaft of claim 1 wherein said means for retaining at least one end of said gripping element against movement as aforesaid comprises a collar fixed to said shaft for rotation therewith, and means connecting said one end of said gripping element to said collar.
 3. The gripping shaft of claim 1 wherein means are provided for retaining the other end of said gripping element against movement in a direction away from said back wall of said groove, said gripping element comprising a flexible member having sufficient slack therein to permit outward movement of said flexible member intermediate The ends thereof into wedging engagement between said shaft portion and a member inserted thereover.
 4. The gripping shaft of claim 3 wherein said means for retaining one end of said gripping element against movement comprises a collar fixed to said shaft for rotation therewith.
 5. The gripping shaft of claim 4 wherein said collar is axially adjustable to vary the slack in said flexible member.
 6. The gripping shaft of claim 4 further comprising an aperture in said collar through which said one end of said flexible member extends, and a sleeve on the projecting end of said flexible member which permits said flexible member to straighten out adjacent said back wall when no force is applied to said flexible member, and limits the outward movement of said flexible member in said groove by engagement of said sleeve with said collar when a force is applied to said flexible member urging said flexible member outwardly in said groove.
 7. The gripping shaft of claim 3 wherein said means for retaining the ends of said flexible member against movement comprises a pair of collars fixed to said shaft in axially spaced relation for rotation therewith, one of said collars being axially adjustable relative to the other for varying the slack in said flexible member.
 8. The gripping shaft of claim 7 wherein said axially adjustable collar is of a diameter greater than the diameter of said shaft portion to provide an adjustable stop for accommodating members of different widths on said shaft portion.
 9. The gripping shaft of claim 1 wherein said gripping element is a flexible member having sufficient slack therein to permit outward movement of said flexible member into wedging engagement between said shaft portion and a member inserted thereover, and a slack adjustment device is provided for varying the amount of slack in said flexible member, said slack adjustment device comprising a collar on said shaft portion containing a longitudinal slot, a guide member received in said longitudinal slot, one end of said flexible member being secured to said guide member, and means for limiting movement of said guide member within said slot in a direction increasing the slack in said flexible member.
 10. The gripping shaft of claim 9 wherein said last-mentioned means comprises a threaded rod on said guide member, an adjustable nut on said threaded rod, and a washer on said rod between said collar and nut which prevents movement of said nut into said slot.
 11. The gripping shaft of claim 9 wherein said last-mentioned means comprises a threaded rod on said guide member, an adjustable nut on said threaded rod, and a radial slot in said collar for confining said nut against longitudinal movement, whereby rotation of said nut in opposite directions causes longitudinal adjustment of said guide member in opposite directions.
 12. The gripping shaft of claim 4 wherein the other end of said flexible member has a ferrule thereon for direct attachment to the outboard end of said shaft portion.
 13. The gripping shaft of claim 12 wherein said outboard end of said shaft portion is sufficiently tapered to provide clearance between said ferrule and the maximum outer diameter of said shaft portion.
 14. The gripping shaft of claim 1 wherein said gripping element comprises a rigid rod, and said means for retaining one end of said rod against movement comprises a collar fixed to said shaft portion for rotation therewith, said collar having a radial slot therein, and said rod having a reverse bend adjacent the outboard end thereof to permit extension of said outboard end of said rod into said radial slot in said collar.
 15. The gripping shaft of claim 14 further comprising means for urging said rod toward said back wall of said groove.
 16. The gripping shaft of claim 15 wherein said last-mentioned means comprises a garter spring disposed around the outboard end of said rod and said shaft portion.
 17. The gripping shaft of claim 14 further comprising a second collar fixed to said shaft portion axially spaced from said first-mentioned collar surrounding the other end of said rod, said second collar having a slot in alignment with said groove in said shaft portion for limiting outward movement of said rod in said groove, and an adjustable spring plunger in said second collar which is compressed by said rod during such outward movement for urging said rod toward said back wall of said groove.
 18. A gripping shaft comprising a shaft portion, a groove in the outer periphery of said shaft portion having a back wall and bottom wall, a gripping element received in said groove, said groove having a depth adjacent said back wall which is greater than the diameter of said gripping element for receipt of said gripping element so as not to interfere with placement of a member onto said shaft portion and removal therefrom, said groove being of less depth in a direction away from said back wall for wedging said gripping element between said shaft portion and member placed thereover when said gripping element is moved along said bottom wall away from said back wall, said gripping element comprising a rigid rod, and means for urging said rod toward said back wall of said groove.
 19. The gripping shaft of claim 18 further comprising a pair of axially spaced collars surrounding the ends of said rod, one of said collars being received on a reduced diameter portion at the outboard end of said shaft portion, said one collar having a maximum diameter no greater than the maximum diameter of said shaft portion, and a radial slot in said one collar, said rod having a reverse bend adjacent the outboard end thereof to permit extension of said outboard end of said rod into said radial slot in said one collar.
 20. The gripping shaft of claim 19 wherein said means for urging said rod toward said back wall of said groove comprises a garter spring disposed around the outboard end of said rod and reduced end portion of said shaft portion.
 21. The gripping shaft of claim 18 wherein said shaft portion has a plurality of said grooves for receipt of a plurality of said rods, and there are a pair of axially spaced collars surrounding opposite ends of said rods, one of said collars being received on a reduced diameter portion at the outboard end of said shaft portion, said one collar having a maximum diameter no greater than the maximum diameter of said shaft portion, and a plurality of axial openings in said one collar, said rods being reversely bent adjacent the outboard ends thereof to permit extension of said outboard ends of said rods into said longitudinal openings in said one collar, and the other collar having radial openings therein which are tapered, and the inboard ends of said rods are outturned for receipt in said radial openings, both of said collars being free to rotate on said shaft portion, whereby when said rods are urged outwardly in said grooves, said rods are caused to move simultaneously due to their connections with said collars for providing a uniform grip between said shaft portion and member inserted thereover.
 22. The gripping shaft of claim 19 wherein said means for urging said rod toward said back wall of said groove comprises a pair of coil springs having one end secured to said shaft portion and the other end secured to the respective collars. 